Sending notifications from a sender to a receiver when going to PAUSED state

[Carlos Rafael Giani]

Hello,

I have a system with UDP-based media transfer. Both sender and receiver 
work already, but to improve some behavior, I'd like to send a UDP 
packet which contains a hint that the sender just went to PAUSED state. 
It is okay if this packet gets lost, as long as this does not happen too 
often.

But what I don't know is how to "inject" a packet right before the 
udpsink starts to block. I can't just inject a packet in the parent 
bin's change_state function, since it is not guaranteed then that the 
packet is the last one transmitted before the udpsink blocks.

Any ideas on how to accomplish this?